The invention relates generally to a method by which decorative patterns may be cut into ceramic surfaces to simulate the appearance of the ceramic hand decoration known as sgraffito. More particularly the invention relates to a method of decorating ceramic surfaces by removing predetermined portions of a coating or glaze to reveal a clay body beneath.
The art of sgraffito has been in practice for centuries. The method of practicing of this art, as far as known, was to make a clay form such as by slip casting, wheel throwing, slab rolling, press molding or combinations thereof. The surface of the clay form is decorated by applying glaze or slip (liquid clay of contrasting color) to selected portions or all of the clay form. Often the glazes or slips would be in bands or patterns involving multicolored glazes or slips. After completing the glazing or slipping, while the clay form is in a leather-hard state (containing considerable moisture but dry enough to be self-supporting form) hand decoration, with the aid of various wooden and/or metal hand tools would be meticulously cut into the damp form. Layers of glaze or slip and underlying clay body are cut away to form a decorative pattern and reveal a contrasting colored clay body beneath the glaze or slip. This procedure is very time consuming and laborous and requires artisans of considerable skill. After carving and drying, the clay form is fired to provide a finished ceramic object.
It has been known in the prior art to use sand blasting to ornament or carve stone-like surfaces and wooden signs and to etch glass. This is typically performed with monuments and the like, whereby a design or letters are cut in granite, marble or other similar materials. Examples of known U.S. patents relating to sand blasting ornamentation, are as follows: U.S. Pat. No. 1,784,495; 2,106,979; 2,358,710; 3,579,926; 3,585,699.
It is an object of the invention to provide a sand blasting method for creating sgraffito type patterns on ceramic surfaces on a mass production type basis, which heretofore has not been practicable and which was previously done by relying on individual hand carving of each object. It is another object of the invention to provide a new and improved method for forming sgraffito type designs of great complexity which, here to now, due to tremendous time and labor involved, have been economically impossible to profitably produce on ceramic bodies, and which is fast and efficient and can be accomplished on a mass production scale. Other objects of the invention will be apparent from the following detailed disclosure.